U.S. Pat. Re. 29,967 describes a cheese making vat composed of an outer, generally oval shell, which is spaced outwardly of an inner processing vessel. The vessel is composed of a pair of generally cylindrical sections that intersect along vertical apices so that the vessel, in horizontal section, has a generally figure-8 shape. An agitator mechanism is located in each cylindrical section and comprises a reversible vertical shaft that carries a radially extending frame composed of a series of vertical and horizontal blades. One edge of each blade is sharpened, while the opposite edge is blunt. When the frame is rotated in the cutting direction, the sharpened edges lead in the direction of rotation to cut the curd and when the frame is rotated in the opposite or stirring direction, the blunt edges lead in the direction of rotation to provide a stirring action.
During the agitation it has been found that the fragile curd particles can be shattered by the sharp apices or edges that connect the cylindrical vessel section, causing fat loss and the generation of excessive fines.
As disclosed in U.S. patent Re.29,967, a plurality of hollow beams space the lower surfaces of the cylindrical sections from the bottom of the outer shell and a heating medium, such as steam, is introduced through a manifold into each of the beams and is discharged from the beams through a plurality of ports which are located along the sides of the beams. The steam them flows upwardly in the space between the cylindrical sections and the shell to heat the curds and whey.
To control the heating, a temperature sensing device is mounted within a well or recess in one of the cylindrical sections of the vessel, as described in U.S. Pat. No. Re. 29,967. During the agitation, a portion of the curds may be directed into the well, with the result that fat loss can occur and excess fines can be developed.
The food processing vat, as disclosed in U.S. Pat. Re. 29,967, also includes one or more swinging blades which are mounted on the frame. The swinging blades are constructed so that when the frame is rotated in the cutting direction, the sharpened edge of the swinging blade will lead in the direction of rotation and when the frame is rotated in the opposite stirring direction, the blade will swing to a position where a side surface is disposed generally normal to the direction of rotation, to thereby provide greater frontal area for stirring.